A 19-year-old woman presents with episodic upper abdominal pain. CT shows a 9 cm well-circumscribed solid and cystic mass in the tail of the pancreas. Biopsy shows sheets of uniform cells with delicate fibrovascular stalks, nuclei oriented away from the vessels, and scattered hyaline globules. Immunohistochemistry shows strong nuclear and cytoplasmic beta-catenin staining. The most likely diagnosis is:

• A Serous cystadenoma
• B Pancreatoblastoma
• C Solid pseudopapillary neoplasm ✓
• D Well-differentiated neuroendocrine tumor

Explanation

Solid pseudopapillary neoplasm typically affects adolescent girls and young women, presenting as a large circumscribed mass. Histology shows monomorphic cells arranged around delicate capillaries with pseudopapillary degeneration away from the vasculature, plus hyaline globules. Aberrant nuclear beta-catenin staining from CTNNB1 mutation is characteristic and distinguishes it from neuroendocrine tumors, which are chromogranin and synaptophysin positive. Pancreatoblastoma occurs mainly in children under 10 years and shows squamoid morules with trilineage differentiation.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.